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Thu, 20 Feb 2025 10:55:11 +0000 (GMT) Message-ID: Date: Thu, 20 Feb 2025 11:55:12 +0100 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 0/3] sched/fair: introduce new scheduler group type group_parked To: Shrikanth Hegde , linux-kernel@vger.kernel.org Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org References: <20250217113252.21796-1-huschle@linux.ibm.com> From: Tobias Huschle In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: Ct2IvKZD6_Q5Diiqy7uyOzOnkv_JcEQ6 X-Proofpoint-ORIG-GUID: vcZh0oNL4zuZdyycl9vyld7y6w1sAvJz X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-20_04,2025-02-20_02,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 phishscore=0 impostorscore=0 bulkscore=0 mlxlogscore=999 adultscore=0 suspectscore=0 lowpriorityscore=0 priorityscore=1501 malwarescore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2502100000 definitions=main-2502200078 On 18/02/2025 06:58, Shrikanth Hegde wrote: [...] >> >> There are a couple of issues and corner cases which need further >> considerations: >> - rt & dl:      Realtime and deadline scheduling require some additional >>                  attention. > > I think we need to address atleast rt, there would be some non percpu > kworker threads which need to move out of parked cpus. > Yea, sounds reasonable. Would probably make sense to go next for that one. >> - ext:          Probably affected as well. Needs some conceptional >>                  thoughts first. >> - raciness:     Right now, there are no synchronization efforts. It needs >>                  to be considered whether those might be necessary or if >>                  it is alright that the parked-state of a CPU might >> change >>                  during load-balancing. >> >> Patches apply to tip:sched/core >> >> The s390 patch serves as a simplified implementation example. > > > Gave it a try on powerpc with the debugfs file. it works for > sched_normal tasks. > That's great to hear! >> >> Tobias Huschle (3): >>    sched/fair: introduce new scheduler group type group_parked >>    sched/fair: adapt scheduler group weight and capacity for parked CPUs >>    s390/topology: Add initial implementation for selection of parked CPUs >> >>   arch/s390/include/asm/smp.h    |   2 + >>   arch/s390/kernel/smp.c         |   5 ++ >>   include/linux/sched/topology.h |  19 ++++++ >>   kernel/sched/core.c            |  13 ++++- >>   kernel/sched/fair.c            | 104 ++++++++++++++++++++++++++++----- >>   kernel/sched/syscalls.c        |   3 + >>   6 files changed, 130 insertions(+), 16 deletions(-) >> >